The mechanisms underlying the role of extracellular materials and cell surface components in the development of organ form during development will be investigated by (1) analyzing the glycosaminoglycan (GAG) degrading activities in embryonic mesenchyme and determining the detailed nature of the products derived from GAG-rich embryonic epithelial basal laminae, (2) establishing whether mesenchymal degradation of embryonic epithelial laminar GAG is a general scheme during the morphogenesis, and (3) investigate the mechanisms by which collagen inhibits laminar GAG degradation.